Too many women do not comply with the American Cancer Society's recommendation for annual breast cancer screenings after age 40, with the result that almost 50 percent of invasive breast tumors are larger and more lethal, palpable masses, according researchers at Massachusetts General Hospital in Boston.

Researchers analyzed the use of mammography in 59,899 women who received 196,891 mammograms at the Massachusetts General Hospital Breast Imaging Division from January 1, 1990 to March 1, 1999.

Six hundred and four invasive breast tumors were found. Also during this period, 206 invasive, clinically detected tumors were seen in women who had no record of having a previous mammogram.

Few of the women who had mammograms returned promptly for their next annual exams; a year and a half after their mammogram, only half of the women had returned, the researchers reported in the journal Cancer.

Researchers concluded that "most tumors probably emerged as larger, palpable masses not because they were missed at the previous negative mammogram, because most were too small then to have been detected, but because too much time had been allowed to pass."

Other Sources: Cancer